Cam grinding machine



g- 5, 1941- c. J. GREEN 2,251,882

CAM GRINDING MACHINE Filed May 17, 1940 3 Sheets-Sheet 1 7 3mm El. ARE/v55 d. GREEN ,g wuammm,

Aug. 5, .1941. c. J. GREEN 2,251,882

CAM GRINDING MACHINE Filed May 17, 1940 v 3 Sheets-Sheet 3 EL. ARE/v51: J. GREEN Patented Aug. 5, 1941 CAM GRINDING MACHINE Clarence J. Green, Worcester, Mass, assignor to Norton Company, Worcester, Mass, a corporation of Massachusetts Application May 17, 1940, Serial No. 335,656

Claims. .(CL 51-101) The invention relates to grinding machines, and more particularly to a camshaft grinding machine.

One object of the invention is to provide a simple and thoroughly practical grinding machine for grinding a plurality of cam blanks on an integral camshaft. A further object of the invention is to provide an improved mechanism for producing a relative feeding movement between the cam blank and the grinding wheel to facilitate grinding the cam blank to a predetermined size and contour. Another object of the invention is to provide an automatic feed controlling mechanism whereby the grinding operation may proceed for a predetermined time interval.

Another object of the invention is to provide a feed control mechanism in which the master cam and master cam roller are relatively moved to control both the contour and sizing of the cam blank. A further object of the invention is to provide an electrically controlled, hydraulically operated feed mechanism relatively to feed a master cam roller to produce the desired and predetermined infeeding movement automatically to size a cam blank. Another object of the invention is to provide a hydraulically actuated feeding mechanism for a master cam roller which is automatically controlled by means of an electrical counting device automatically to separate the master cam and the master cam roller after a predetermined grinding operation has been completed. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of the possible embodiments of the mechanical features of thi invention,

Fig. 1 is a fragmentary front elevation of a cam grinding machine embodying this invention;

Fig. 2 is a fragmentary rear elevation, on an enlarged scale, of the master cam and master cam roller assembly together with their actuating mechanism;

Fig. 3 is a fragmentary cross sectional view, taken approximately on the line 33 of Fig. 2, showing the details of the cam feeding mechanism;

Fig. 4 is a fragmentary sectional view, on a reduced scale, taken approximately on the line 4-4 of Fig. 3; and

Fig. 5 is a combined electric wiring diagram and hydraulic piping diagram of the control and actuating mechanism of the machine.

A cam grinding machine has been illustrated in the drawings, having a base which supports a longitudinally traversable work supporting table II on a flat way I2 and a V-way 13. The base It) also supports a rotatable grinding wheel I4 which is mounted on a wheel spindle l5 journalled in bearings (not shown) in a transversely movable wheel slide 16. The wheel slide l6 may be adjusted transversely relative to the base 10 by a wheel feeding mechanism which is old and well known in the grinding art such as, for example, that shown in the prior U. S. patent to Norton, No. 762,838, dated June 14, 1904, to which reference may be had for details of dis closure not contained herein. The wheel feeding mechanism may be actuated either manually or automatically as desired.

In the preferred construction, the wheel slide I6 is provided with a depending nut 19 which meshes with or engages a rotatable cross feed screw 20 which is rotatably supported in bearings (not shown) in the base Ill. The feed screw 20 is provided with an integral shaft 2| which extends from the front of the machine base. A gear 22 is mounted on the front .end of the shaft 21 and meshes with a small gear or pinion (not shown) which is arranged to be rotated by means of a manually operable feed wheel 23. The feed wheel 23 is provided with a micrometer adjusting mechanism 24 by means of which a stop abutment 25 may be readily adjusted as desired. A pivotally mounted stop pawl 26 cooperates with the stop abutment 25 and serves to limit the approaching movement of the wheel slide I6 to locate it in a predetermined grinding position. In the present cam grinding machine, the mechanism just described for adjusting the grinding wheel 14 transversely is provided merely for adjusting the position of the wheel in setting up the machine for a given grinding operation, to feed the grinding wheel 14 during a truing operation, or to compensate for wear of the grinding wheel I4 during production grinding.

The work supporting table I I may be traversed or reciprocated longitudinally either automatically or manually relative to the base I0. A manually operable traversing mechanism has been illustrated for traversing the table I l longitudinally. This mechanism comprises a manually operable rotatable traverse wheel 28 which is rotatably supported on a shaft 29. A gear is mounted on the shaft 29 to rotatewith the hand wheel gear mechanism above described to produce a longitudinal traversing movement of the rack bar 34 and the table H. The direction of movement of the rack bar 34 and table II is determined by the direction of rotation of the hand wheel 23.

The longitudinally movablejwork table i I supports a pivotally mounted rock bar 35. The rock bar 35 is supported in bearings 36 (Fig. 1)

and 2'! (Fig. 2) each of which is fixedly mounted on the upper surface of the table H. The rock bar 35 is arranged so that it may be rocked about anaxis'which' is substantially parallel to the axis ofrotation of the grinding wheel 14. The rock bar 35 is providedwith a rotatable shaft or headstock spindle which, as illustrated in the drawings, may be designated as a master camshaft 38 having a camshaft supporting center 39. The master camshaft 38 is supported in bearings (Fig. 1) and 41 (Fig. 2) which are in turn supported on or formed integral with the rock bar 35.. The rock bar 35 also supports a footstock 42 which is provided with a footstock center 43. The headstock center 39 and the footstock center 43 are; arranged rotatably to support a camshaft 4.4 having a plurality of jcams 45 to be ground.

In orderthat the cams 45 on the camshaft 44 may be ground to a predetermined sizeand contour, it is desirable to provide a plurality of master cams, 48 for controlling .the rocking movement of the rock bar 35 sov as to .rock the camshaft 44 being ground toward and from the periphery of the. grinding wheel i4 so as to'generate a predetermined shape on the. cam blanks d5. A plurality: of master cams 48 are mounted on the master camshaft 38 in axial .alignment with the axisof the camshaft .being ground.

Afmastercam roller 49 is slidably keyed on a rotatable shaft 50 which is rotatably supported in a. pair of spaced bearings 5i and 52. The bearings 5i and '52 are carried by a pivotally mounted frame 53 which is pivotally supported on'fa shaft 54.. The shaft 54, is journalled in a frame 55. whichis supported in fixed relationship With-the table! I.

The master cam roller 49 is preferably indexed automatically as the table H is traversed longitudinallyv automatically to position the master cam roller 49 opposite the master cam 48 which corresponds to the cam 45 being ground on the camshaft 44 to .be ground. The details of the master cam roller indexing mechanism have not beenrillus'trated since this feature is not considered'to bea part of the present invention. Fora-detailed disclosure of the automatic shifting mechanism for the, master cam roller, reference may behad to the prior U. S. Patent No. 1,783,755 to Trefethen and Belden dated December 2, 1-980, and also 'to the U. S.-Patent No. 2,022,178 to Belden' and Silven, dated November 26,:"1935; The automatic indexing mechanism may comprise a dog bar 50 which is anchored at one end by means of a bracket 6! to the base It. Theidogba'r 59 is slidably supported in brackets 6:2v iand763 which. are formed integral with the frame js'othat as the table H and the frame 55 are moved longitudinally during a positioning movement of the camshaft 44, the brackets 62 and 63 will slide along the dog bar 60, thus serving as a support for the dog bar (ill. The dog bar is provided with a plurality of adjustable dogs 64 which are arranged to engage a star wheel 65 when the table is traversed longitudinally. The star wheel 65 is supported on a stud 65. The stud 66 also supports a gear 67 which is mounted to rotate with the star Wheel 65. The gear 61 meshes with a gear 68 which is rotatably supported on a stud 59. The gear 68 meshes with a gear 78 which is rotatably supported on a stud l l.

A gear 12 is formed integral with the gear 10 and meshes with a rack bar '13. The rack bar 13 is slidably supported in a channel-shaped frame 14 (Fig. 3) A yoke-shaped member 15 is fixedly F drive or a motor attached to the machine.

mounted to the rack bar F3. The yoke-shaped member 15 straddles the master cam roller 49 and'is' arranged to move the master cam roller 49 longitudinally when the rack bar 13 is moved automatically to position the master cam roller '49 opposite the master cam 48 which corresponds with the cam 45 being ground. The adjustable dogs 54 are positioned along the dog bar 60 in position to correspond with the spacing of the cams 45 on the camshaft 44 so that when the table NY is traversed longitudinally to position a predetermined cam 45 in operative position opposite the grinding wheel I 4, the dogs 54, through the star wheel 55 and the gear train previously described, will index the rack bar 13 longitudinally automatically to index the master cam roller 49 into position opposite a predetermined master cam 48. For details of disclosure of this indexing mechanism not contained herein, reference may be had to the prior U. S. patents above referred to.

A work driving mechanism is provided for rotating the camshaft 44 being ground. As illustrated in the drawings, this mechanism may comprise a driving belt 8!] which is driven from any suitable source of power, such as an overhead The belt 80 drives a pulley 8| which is mounted on the end of a rotatable shaft 82. The shaft 82 is supported by a bracket 83 which is fixed to the upper surface of the table 1 I. In order to drive the master camshaft 38 and the product camshaft 44 uniformly during the rocking movement of the rock bar, a universal driving connection is provided comprising a universal joint 84 which is connected between the shaft 82 and a connecting shaft 85. The shaft 85 is connected by a second universal joint 85 with the end of the master camshaft 33 uniformly to rotate the same during the rocking movement of the rock bar 35.

It is desirable to provide a yieldable device whereby the master cam 48 may be maintained in operative contact with the master cam follower roller "49 during the rotation of the master camshaft 35 in order to impart the desired oscillatory movement to the rock bar 35 so as to generate a predetermined contour on the cam 45 being ground. The rock bar35 is provided with an outwardly extending lever or arm (Figs. 3 and 5). 82 which is in turn supported by the frame 55. A slidably mounted piston 93 is contained within the cylinder 9!.

95 at the other end to the arm 90. A spring 96 A cylinder 9| is supported in a bracket A piston rod 94 is connected to; the piston 93 at one end and by means of a stud piston rod 94 and is interposed between the piston 93 and a bushing 91 which is mounted within the lower end of the cylinder 9|. The spring 96 is a compression type spring and serves normally to exert a pressure tending to rock the rock bar 35 in a clockwise direction (Figs. 3 and 5) to maintain the master earns 48 in operative engagement with the master cam roller 49. The axis of the master cam roller 49 being relatively stationary, a rotary motion of the master camshaft 38 and master cams 48 produces a rocking or oscillating movement of the rock bar 35 to impart a corresponding oscillating movement to the cam 45 being ground to produce a predetermined contour thereon.

It is desirable to provide a suitable mechanism for separating the master cam 48 and the follower roller 49 when the table I I is traversed longitudinally to position a new cam 45 in operative position opposite the grinding wheel I4. In the preferred construction, a fluid pressure mechanism is provided comprising a fluid pressure cylinder I which is supported on the frame 55. A piston IOI is slidably mounted within the cylinder I00 and is connected to one end of a piston rod I02. The lower end of the piston rod I02 rides on the end of an adjustable stop screw I03 which is carried by the outer end of the arm 90 (Figs. 3 and 5) It will be readily apparent from the foregoing disclosure that when fluid under pressure is admitted to a cylinder chamber I04, the piston IOI is forced downwardly so that the piston rod I02 engaging the screw I03 rocks the lever 90 and the rock bar 35 in a counterclockwise direction into the position illustrated in Fig. 3 until the lever 90 engages a stop screw 09 which serves to restrict the separating movement.

A fluid pressure system is provided for supplying fluid under pressure to the cylinder I00 as well as to a feeding mechanism to be hereinafter described. A reservoir I05 is provided in the base #0 of the machine. Fluid is pumped from the reservoir I05 through a pipe I05 by means of a motor driven fluid pressure pump I01 and passes fluid under pressure through a pipe I08 to a control valve I05. A variable pressure relief valve H5 is connected in the pipe line I08 to return excess fluid under pressure through a pipe III to the reservoir I05 in case the pressure within the system increases over the desired and predetermined pressure. The control valve I09 is a piston type control Valve comprising a valve stem II2 having valve pistons H3, H4, H5 and H6 formed integrally therewith. The valve stem I I2 is normally held in its left-hand end position (Fig. 5) by means of a compression spring II! which surrounds the left-hand projecting end of the valve stem I I2 and is interposed between nuts H9 and a valve head H0. An electric solenoid I of the pull type is provided to shift the control valve I09 into its reverse position, that is, toward the right (Fig. 5) V In the position of the valve I09 (Fig. 5), fluid under pressure passing through the pipe I08 enters a valve chamber I2I located between the valve pistons H4 and I I5 and passes out through a pipe I22, through an adjustable throttle valve I23, and a pipe I24, into the cylinder chamber I04 to move the piston IOI downwardly into the position illustrated in Fig. 5, thereby rocking the rock bar to move it to an inoperative position, thus separating the master cam 48 from the master cam roller 49 and the product cam from the grinding wheel I4 so as to facilitate a traversing movement of the table I I to position the next cam opposite the grinding wheel I4. When the solenoid I20 is energized, the valve I09 is shifted into its right-hand position (Fig. 5) so that fluid within the cylinder chamber I04 may exhaust through the pipe I22, through a valve chamber I25 located between the valve pistons H3 and II 4, and pass outwardly through a pipe I25, an adjustable throttle valve I21, and a pipe I28, into the reservoir I05. By adjustment of the valve I23, the speed of movement of the rock bar 35 toward and from an operative posiiton may be adjusted as desired. By adjustment ofthe throttle valve I2I, the exhaust of fluid from the cylinder chamber I04 may be varied as desired to control the rocking movement of the bar 35 in a counterclockwise direction. When the pipe I22 is open to the exhaust, as above described, the released compression of the spring 96 serves to rock the bar 35 to an operative position and the throttle valve I23 serves to control the speed of exhaust of fluid and thereby to control the speed of movement of the rock bar 35.

In order to grind a cam blank not only to a predetermined contour but also to a predetermined size, it is desirable to provide a feeding mechanism for causing a relative approaching and receding movement between the axis of the cam 45 being ground and the grinding wheel I4. In the preferred form of this invention, I provide a feeding mechanism which causes the master cam roller 49 to approach or recede from the axis of the grinding wheel I4 so as to change the position of the stroke of oscillation of the rock bar 35 to produce either a relative approaching or a receding movement between the cam 45 being ground and the grinding wheel I4.

A feeding mechanism is provided for controlling the transverse feeding movement of the master cam roller 43 so as to impart the desired relative feeding movement between the cam 45 being ground and the grinding wheel I4. This mechanism is preferably a fluid pressure mechanism comprising a hydraulic cylinder I30 which contains a slidably mounted piston I3I. A piston rod I32 is connected to the piston I3I. The piston rod I32 projects from the right-hand end of the cylinder I30 (Figs. 3 and 5) and is provided at its outer end with a transversely arranged pin or stud I33 which engages slots I34 formed in the upper yoke-shaped end I35 of an upwardly extending arm I33. The arm I35 is preferably formed as an integral part of the oscillatable frame 53 which supports the master cam roller 49 and its supporting shaft 50.

It will be readily apparent from the foregoing disclosure that movement of the piston I3I will be imparted through the lever I36 and the frame 53. Movement of the frame 53 and lever I35 in a clockwise direction (Figs. 3 and 5) is limited by an adjustable stop screw I34, thus limiting the separating movement of the master cam roller 43. The lever I30 and the frame 53 may move from the full line position I36 shown in Figs. 3 and 5 into the broken line position I39a (Fig. 5). The admission of fluid to and the exhaust of fluid from the cylinder I30 is preferably controlled by means of the control valve I09. A pipe I 38 is connected between the pipe I22 and a cylinder chamber I39. Similarly a pipe I4!) is connected between the valve I09 and a cylinder chamber I4I formed at the left-hand end of the piston I3I'. The cylinder I30 and piston ISI serve to produce a rapid approaching movement of the master cam roller 49 rapidly to rock the bar 35 to bring the product cam 45 into .a grinding position adjacent to the operative surface of the grinding wheel I4.

In the position of the valve I99 (Fig. fluid under pressure from the pump I01 passing through the pipe I03, the valve chamber I2I, the pipe I22, the pipe I38, into the cylinder chamber I139, moves the piston iSI toward the left-hand end of the cylinder I30 into the position illustrated in Figs. 3 and 5 to move the rock bar 35so as to separate the cam 45 being ground fromthe operative face of the grinding wheel after a grinding operation has been completed. During this movement, fluid within the cylinder chamber MI is exhausted through the pipe I40, through a valve chamber E42 located between the valve pistons H5 and H0, through a port into a central aperture I43 within the valve stem member H2, and passes outwardly into the valve chamber I25 located between the valve pistons H3 and H4 and out through an exhaust pipe I26 and a throttle valve I21 into the reservoir I05. The speed of movement of the piston I3I in the direction above described, that is, toward the left (Figs. 3 and 5) may be readily controlled by adjusting the throttle valve I21 as desired. A pipe I44 is connected to chambers at each end of the valve I09 and serves as an exhaust pipe to cause any fluid leakage by the valve pistons to drain directly through an unrestricted passage which is always open to return such fluid to the reservoir I05, thus facilitating free movement of the control valve I09.

It is desirable to provide a slow relative approaching movement between the cam 45 being ground and the grinding wheel I4. In the preferred form, a feed regulating mechanism is provided for modifying the rapid approaching movement of the cam 45 and the grinding wheel I4 caused by the piston I3I to obtain a controlled and predetermined relative infeeding movement between the cam 45 and the grinding wheel I4. In the preferred construction, a self-contained dash pot feed regulator is provided, of the type such as that shown in the prior U. S. patent to B. H. Goehring, No. 2,151,660, dated May 21, 1939. This mechanism may comprise a pair of dash pot cylinders I50 and I 5| which contain dash pot pistons I52 and I53, respectively. The dash pot pistons I52 and I53 and their respective cylinders I50 and I 5| are arranged with their axes parallel to each other and spaced on diametrically opposite sides of an extension I54 of the piston rod I32. The dash pot cylinders I50 and I5! are supported in a casing I55 which is aflixed to the end of the cylinder I30. The dash pot pistons I52 and I53 are normally held in a left-hand end position by means of springs I59 and I51, respectively. An adjustable stop screw I58 serves to limit the movement of the dash pot pistons I52 and I53 in a direction toward the left (Fig. 5). A slida-bly mounted sleeve I59 having an integral flange I60 is slidably supported on the extension I54 of the piston rod I 32. The flange I60 is arranged to engage the left-hand end faces of the dash pot pistons I52 and I53, respectively. The stop screw I58 engages the flange I90 and thereby serves to limit not only the movement of the flange I60 in a left-hand direction but also the movements of the dash pot pistons I52 and I53, respectively. An adjustable stop collar I6I is mounted on a screw threaded portion I62 of the piston rod extension I54. An adjustably mounted stop collar I63 is supported on the sleeve I59 and may be adjusted relative thereto by means of a collar. 164 which is screw threaded onto a threaded portion I65 of the sleeve I59.

The rapid forward feeding movement of the master'cam roller 49 and the product camshaft 44 continues until the collar ISI engages the end of the sleeve I59. Continued movement of the piston rod IL32 moves the sleeve I59 and flange I=60 toward the right and continued movement serves to move the dash pot pistons I52 and I53 in a direction toward the right. As soon as the dash pot pistons I52 and I53 start moving toward the right, the rapid approaching feed is reduced to a slower predetermined grinding feed due to the fact that fluid confined Within the dash pot cylinders I50 and I5I respectively, which are interconnected by a passage I 66, exhausts through the passage I61 and a needle Valve I68 into a chamber I69 which is connected with a reservoir I10. Fluid may also exhaust through a passage I1] and a pipe I12 through an adjustable throttle valve I13 and a pipe I14 into the chamber I69 and reservoir I10. Either the needle valve IE8 or the adjustable throttle valve I13 or both may be used to control the rate of exhaust of fluid from the dash pot cylinders 50 and I5I. The slow grinding feed continues until the adjustable stop sleeve I63 engages the end face I15 of the dash pot casing which serves positively to limit the forward feeding movement of the master cam roller 49 and the product camshaft 44 relatively toward the grinding wheel I4 to stop the forward grinding infeed when the cam 45 has been reduced to substantially the predetermined desired size and contour.

When fluid under pressure is reversed to shift the fluid pressure operated piston I3I into the position illustrated in Figs. 3 and 5, the released compression of the springs I55 and I51 serves to move the dash pot pistons I52 and I53, respectively, into the left-hand end position (Fig. 5). During this movement, fluid from the reservoir I10 is drawn through the pipe I14 and a pipe I16 and ball check valve I11 again to refill the dash pot cylinders I50 and I5I ready for the next infeeding movement.

In order to maintain the desired level of fluid within the reservoir I10, a pipe I18 is connected with the pressure pipe line I08 to pass fluid through a valve I19 and a pipe I into the chamber I69 and reservoir I10. An overflow pipe I 8| serves to return fluid to the reservoir I05 in case the fluid within the reservoir I10 rises above a desired pipe. If desired, the valve I 19 may be left slightly open so that the reservoir I19 is at all times maintained with its level up to the aperture adjacent to the end of the pipe I8I. In normal use, however, the valve I19 is used-merely to replenish the supply of fluid within the reservoir I10 periodically when necessary.

It is desirable to provide a control device whereby the cam 45 being ground may be maintained in its forward feeding position for a predetermined finish grinding operation. This is preferably accomplished by means of an electrical control apparatus comprising an electrical impulse time relay or counter I85, such as, for example, the Microflex instantaneous reset counter or relay which is manufactured by the Eagle Signal Corporation of Moline, Illinois. A normally open limit switch I36 is mounted in fixed relationship with the table I I and is arranged so that its actuating plunger I82 is en- =erates to break the circuit, thereby deenergizgaged and actuated each time the rock bar 35 is oscillated by means of an arm I81 which is adjustably supported on the rock bar 35. The relay I85 may be adjusted so that after a predetermined number of electrical impulses, the relay or counter I85 operates to close a circuit to deenergize the solenoid I20, thereby releasing the compression of the spring I I! to shift the control valve I09 toward the left (Fig. which serves to reverse the direction of flow of fluid to the cylinder I30. A push button switch 33 serves as a stop and start switch to render the timer or counter I85 operative at the start of the grinding operation. The switch I83 and the circuit previously described are supplied by power from any suitable source which has for the sake of illustration been indicated by the power line I84.

The operation of this improved cam grinding machine will be readily apparent from the foregoing disclosure. Assuming all of the parts to have been previously adjusted, a camshaft 44 is mounted in operative position on the work supporting centers 39 and 43, the camshaft 44 is started rotating, and the table II is traversed longitudinally by means of the hand wheel 20 to position the end cam 45 on the camshaft 44 in operative position opposite the grinding wheel I4. The push butt-on I83 is then closed to energize the solenoid I20 and at the same time render the Microflex instantaneous reset counter I 85 operative. The energizing of the solenoid I20 shifts the valve I09 toward the right (Fig. 5) into the reverse position to admit fluid from the pump I01 through the pipe I08, through the valve chamber I2I and the pipe I40, into the cylinder chamber I4I, to move the piston I3I toward the-right (Fig. 5) to cause a rapid approaching movement of the master cam roller 49 and also of the camshaft 44 to be ground. At the same time, the shifting of the valve I09 serves to open the pipe line I22 to the exhaust so that the released compression of the spring 95 serves to rock the rock bar 35 in a clockwise direction (Figs. 3 and 5), thus forcing the piston I5! upwardly and exhausting fluid from the cylinder chamber I54 through the pipe I24, the valve I23, the pipe I22, the valve chamber I25, and out through the exhaust pipe I26 into the reservoir I05. The speed of movement of the rock bar 35 into an operative position may be controlled by the valve I23. The infeeding movement of the master cam roller 49 continues at a rapid rate until the collar ISI engages the end of the sleeve I 59, after which the sleeve I59 starts movement of the dash pot pistons I52 and I53. The movement of the dash pot pistons I52 and I 53 sets up a back pressure which reduces the rapid approaching movement to a slow grinding speed. The grinding feed continues until the collar H33 engages the surfaces I which stops the infeeding movement of the master cam roller 49 when the work piece is ground to approximately a desired predetermined size. The grinding operation continues, however, allowing the grinding wheel I4 to grind out or finish grind the work.

Each oscillation of the rock bar 35 during the grinding operation serves through the arm I81 to close the limit switch I82 instantaneously, thus imparting an electrical impulse to the Microflex instantaneous reset counter I05. After a predetermined number of oscillations of the rock bar 35. that is, rotations of the master cams and th cam 45 being ground, the time relay oping the relay I20. As soonas the rel y I20 is deenergized, the released compression of the spring III shifts the valve stem II2 rapidly into the position illustrated in Fig. 5 to reverse the flow of fluid to the cylinder I30 so as to admit fluid into the'cylinder chamber I39 to move the piston I3I'toward the left (Figs. 3 and 5) to move the master cam roller 49 to an inoperative position. At the same time, fluid is admitted through the pipe I22, through the valve I23 and pipe i24,into the'cylinder chamber I04 to cause a downward movement of the piston IOI, thus rocking the rock bar 35 in a counterclockwise direction (Figs. 3and 5)v to rock the master camshaft and the product cams 44 being ground to an inoperative position; thus separating the cam 45 which has been groundfrom the grinding wheel I4 so as to facilitate a traversing movement of the table. The hand wheel 28 may then be rotated to traverse the table II longitudinally to position the next cam 45 in operative relation opposite the operative face of the grinding wheel I4; When the table II and the next cam 45have been thus positioned, the push button I83 may again be closed to stop the next grinding cycle, which cycle'is repeated as above described until all of the cams on the camshaft have been ground to the desired and predetermined size. and

contour. r

In case it is necessary to compensate for wheel wear, that is, wearing away of the operative face of the grinding wheel I4, this may be accom pli'shed by adjustment of the feed wheel 24to advance the grinding wheel slide I5 by an'amount equal to the wheel wear.

It will thus beseen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cam grinding machine having a rotatable grinding wheel, a rock bar, a rotatable camshaft support on said rock bar, means including a master cam and a follower roller to impart an oscillatory movement to the rock bar to gen-' erate a predetermined contour on a cam blank, and a feeding mechanism for moving said roller transversely including a hydraulic piston and cylinder operatively connected to impart a comparatively rapid transverse movement to said follower roller to rock said bar and position a cam blank adjacent to the operative face of the grinding wheel, and a hydraulic feed regulator operatively connected with said piston and cylinder to reduce the rapid transverse movement of the follower roller to a slow transverse movement to control the oscillation of the rock bar so as to produce a grinding feed.

2. In a cam grinding machine having a rotatable grinding wheel, a rock bar, a rotatable camshaft on said rock bar, means including a master cam and a follower roller to impart an oscillatory movement to said rock bar to generate a predetermined contour on a cam blank, a pivotally mounted frame to support said follower roller, and means including a fluid pressure piston operatively connected to swing said frame to produce a transverse movement of, they follower roller so as :to impart a: transverse feeding movement of a: cam blank1re1ative-to-the grinding wheel to grinda: camzblank to-a predetermined size and contour. I

3;- In a-camgrinding machine having a rotatable grinding wheel, a rockbar, arotatable camshaft support onsaidrock'bar, means including amaster cam and a follower roller to impart an oscillatory movement to -the rock bar to generate a predetermined contour on a cam blank, a pivotally mounted frame to support said'fo-llower roller; means including a fluid pressure operatedp'piston and cylinder operatively connected to-swingsaid frame'to' produce a comparatively rapid-transverse movement of the follower, and a dash; pot piston. and cylinder operatively cone nected therewith; to reduce therapid transverse movement of the roller to aslow grinding feed.

4.- In a cam grinding machine having a rotatable grinding wheel; a rock' bar, a rotatable camshaft supporti on saidrock bar, a master cam andva'follower to impart. an oscillatory movement to: the rock barto generate apredetermined icon tour on; a cam blank, means including'a fluid pressure piston and cylinder: to move said rock barrto separat'e the master: cam from the follower roller;v a'xp'ivotally mountedframe to. support said follower roller; a feeding: mechanism including a fluid pressure operated piston and cylinders-operatively connected: to swing. said frame to producea relative-transverse. movement of the follower roller to: impart a feeding movement to said cam blank, means including-a control valve operatively connected tocontrol theadmission of fluid to said rock bar cylinder-and to said feed cylinder, anelectrical time delay relay to control said valve, and means including a switch actuated by and in timed relation with the oscillation of the rock bar automatically through said relay to shift said control valve after a predetermined time interval to admit fluid under pressure to rock the bar to an inoperative position and to admit fluid to said feed cylinder to move the master cam roller transversely to an inoperative position.

5. In a cam grinding machine having a rotatable grinding wheel, a rock bar, a camshaft support on said rock bar, a master cam and a follower to impart an oscillatory movement to the rock bar to generate a predetermined contour on a cam blank, means including a piston and cylinder to move said rock bar to separate the master cam from the follower roller, apivotally mounted frame to support said follower roller, a feeding mechanism including a piston and cylinder operatively connected to swing said frame to produce a relative transverse movement of the follower to impart a feeding movement to said cam-blank, a control valve operatively connected tovcontrol the admission of fluid to said rock bar cylinder and to said feed cylinder, a solenoidto move said valve to an operative position, an electrical time delay relay which.is op-' eratively connected to deenergize said solenoid after apredetermined time interval, and means including a switch actuated by and in timed relation with the oscillation of the rock bar automatically to control said time delay relay so as toadmit fluid under pressure to rock the bar to an inoperative position and to admit fluid to the feed cylinder to move the master cam roller transversely to an inoperative position after a predetermined time interval.

CLARENCE J. GREEN. 

